Techopedia explains Private File Sharing

Private file sharing typically requires setting up a private connection or network. This network can be:

Peer-to-peer network

Local or wide area personal/corporate network

Virtual private network (VPN)

Private or secure public cloud

The file sharer has the ability to allow or restrict individuals on preference. For example, when sharing a document on Google Docs, only users that are allowed by the file owner are able to view/edit the file. Private file sharing may also apply file encryption algorithms on the file being shared, so even if the underlying connection is compromised, the contents of the file are not revealed until correct cryptographic keys are provided.